From the moment that Mr. Bush made his intention of invading Iraq clear, the question was never whether American troops would succeed, or whether the regime they toppled would not be exposed to the world as a despicable one. The question was, and still is, whether the administration has the patience to rebuild Iraq and set it on a course toward stable, enlightened governance. The chaotic situation in Afghanistan is no billboard for American talent at nation-building. The American administration of postwar Iraq has so far failed to match the efficiency and effectiveness of the military invasion. But as the United States came to the end of one phase of the Iraqi engagement last night, there was still time to do better.